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Anthropology 1: Introduction to Physical Anthropology Lecture 12 – 4/5/10: Primate Intelligence SMC Spring 2010 Rebecca Fr...
The main question <ul><li>Why are primates so smart? </li></ul>
The main question <ul><li>Why are primates so smart? </li></ul><ul><li>Big brains are costly: metabolism alone consumes 20...
What is “Intelligence”? <ul><li>Intelligence not just one thing that you have more of or less of </li></ul><ul><li>Some an...
Monkeys and apes have big & complex brains Galago Rhesus Chimpanzee
Relative brain size Primates
Why are costly brains worthwhile? <ul><li>Our brains are expensive  </li></ul><ul><ul><li>Make up 2% of body weight </li><...
Why be flexible? <ul><li>Built-in behavioral strategies work in many situations </li></ul><ul><li>When conditions are stab...
Flexible Problem Solving <ul><li>Cognitive abilities evolve to solve the adaptive problems a species faces </li></ul><ul><...
Learning and problem solving may also be useful in other contexts too <ul><li>Solving complex  ecological  problems </li><...
Testing Hypotheses <ul><li>Are  ecological  or  social  factors better predictors of brain (especially neocortex) size? </...
 
Ecological Intelligence Hypothesis <ul><li>Finding food is complicated </li></ul><ul><ul><li>Where is it? </li></ul></ul><...
Ecological Intelligence Hypothesis 1: Frugivory <ul><li>Exploiting short-lived, patchy food resources (fruits) may have fa...
What do primates know about fruit? <ul><li>Japanese macaques know  </li></ul><ul><ul><li>Fruit grows on trees, candy doesn...
What do primates know about maps? (Spatial representations) <ul><li>In tropical forests, huge diversity of plant species <...
Primates would like google maps… <ul><li>Primates seem to know  </li></ul><ul><ul><li>What is edible </li></ul></ul><ul><u...
Does frugivory correlate with large brains? A little, but not strongly
Looking at the correlation between the color vision portion of the brain and neocortex, the correlation is stronger  <ul><...
Ecological Intelligence Hypothesis 2: Extractive Foraging <ul><li>Exploiting foods that are difficult to process, may have...
Examples of extractive foraging <ul><li>Baboons dig up underground food </li></ul>
Examples of extractive foraging <ul><li>Baboons dig up underground food </li></ul><ul><li>Capuchins extract food from  </l...
Examples of extractive foraging <ul><li>Baboons dig up underground food </li></ul><ul><li>Capuchins extract food from  </l...
<ul><li>Orangutans eat durian, neesia fruits </li></ul><ul><ul><li>Protected by tough or spiny shells </li></ul></ul><ul><...
<ul><li>Mountain gorillas’ foods are abundant, but well defended </li></ul>Examples of extractive foraging bamboo wild cel...
<ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging Chimps fish for ants in tree nests
<ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging Chimps fish for termites
<ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging Chimps extract honey
<ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging West African chimps use rocks to bash o...
Does use of extractive foods correlate with large brains? Not really
Other problems with ecological intelligence hypothesis  <ul><li>Extent of frugivory related to brain size  </li></ul><ul><...
Social Intelligence Hypothesis <ul><li>Dunbar: “social intelligence” </li></ul><ul><li>Humphrey: “social chess” </li></ul>...
<ul><li>Primates live in relatively large groups </li></ul><ul><li>Primates track social information </li></ul><ul><ul><li...
<ul><li>Primates recognize others as individuals and keep track of group membership  </li></ul><ul><li>Know members of own...
<ul><li>Monkeys seem to know a lot about their own relationships  </li></ul><ul><li>Distinguish kin from nonkin </li></ul>...
Social Intelligence <ul><li>Monkeys know about kinship relationships of others </li></ul><ul><li>When vervet infants screa...
Social Intelligence <ul><li>Triadic awareness  of rank & friendship in some species </li></ul><ul><li>Is A better friends ...
Social Intelligence <ul><li>Baboons know something about others’ rank relationships </li></ul><ul><li>Grunt is affiliative...
Social Intelligence <ul><li>Knowledge of others’ relationships useful when fights occur </li></ul><ul><li>Able to predict ...
Social Intelligence <ul><li>Monkeys can predict what others will do </li></ul><ul><li>Macaques and  baboons often grunt wh...
A special kind of intelligence <ul><li>“ Theory of Mind” or “Mindreading” </li></ul><ul><li>The ability to infer what othe...
Theory of Mind <ul><li>In humans, ToM develops in early childhood </li></ul><ul><li>Common experiment to test for ToM </li...
<ul><li>Monkeys appear to know relatively little about what others know </li></ul><ul><li>Vervet mothers don’t warn infant...
Theory of Mind <ul><li>Apes may know more about what others know </li></ul><ul><li>Recognize self in mirror </li></ul><ul>...
Do Chimps have theory of mind? (Povinelli et al. 1996)  Test whether seeing = knowing  <ul><li>Chimps allowed to chose whi...
But they do not prefer… <ul><li>Human w/eyes open to human w/eyes closed </li></ul><ul><li>Human w/blindfold over mouth to...
But: chimps are sensitive to what others know in food competition <ul><li>Brian Hare and colleagues devised a test of theo...
Ecological Realism <ul><li>Often, lab tests like Povinelli’s are poor tests </li></ul><ul><li>Don’t look at skills being u...
Other contexts of mindreading we haven’t studied much…  <ul><li>Cooperative hunting </li></ul><ul><li>Stalking prey </li><...
Apes’ cognitive abilities are hotly debated <ul><li>Some think apes have considerable knowledge of others’ minds </li></ul...
Testing Hypotheses <ul><li>Are  ecological  or  social  factors better predictors of brain (especially neocortex) size? </...
Figure 09.07c Does social complexity correlate with large brains? Yes: better than with frugivory or extraction
Except… <ul><li>Social intelligence hypothesis doesn’t explain why apes are smarter than monkeys </li></ul><ul><li>Apes al...
Big brains may also be linked to particular types of social challenges <ul><li>Generally larger neocortex ratio as clique ...
Brain size may be the result of selection for flexible behavior in BOTH ecological & social domains <ul><li>Compare “execu...
So which is it?  Ecological or social intelligence that drove primate brain growth? <ul><li>Answer isn’t clear </li></ul><...
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Primate intelligence

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Primate intelligence

  1. 1. Anthropology 1: Introduction to Physical Anthropology Lecture 12 – 4/5/10: Primate Intelligence SMC Spring 2010 Rebecca Frank
  2. 2. The main question <ul><li>Why are primates so smart? </li></ul>
  3. 3. The main question <ul><li>Why are primates so smart? </li></ul><ul><li>Big brains are costly: metabolism alone consumes 20% of daily energy budget in humans </li></ul><ul><li>If it weren’t good for something, selection would eliminate it… </li></ul><ul><li>What are the benefits that lead to the evolution of large brains / intelligence in primates? </li></ul>
  4. 4. What is “Intelligence”? <ul><li>Intelligence not just one thing that you have more of or less of </li></ul><ul><li>Some animals quite smart at limited skills, e.g., memory, navigation, communication </li></ul><ul><li>Many psychologists think “intelligence” = adding together of more and more specialized skills </li></ul>Nutcrackers, chickadees: spatial memory Buntings: celestial navigation Bees: waggle dance
  5. 5. Monkeys and apes have big & complex brains Galago Rhesus Chimpanzee
  6. 6. Relative brain size Primates
  7. 7. Why are costly brains worthwhile? <ul><li>Our brains are expensive </li></ul><ul><ul><li>Make up 2% of body weight </li></ul></ul><ul><ul><li>Consume 20% of metabolic energy </li></ul></ul><ul><li>Some animals get by with tiny brains </li></ul><ul><li>What are the benefits of a big neocortex? </li></ul><ul><ul><li>Learning </li></ul></ul><ul><ul><li>Problem solving </li></ul></ul>
  8. 8. Why be flexible? <ul><li>Built-in behavioral strategies work in many situations </li></ul><ul><li>When conditions are stable, little need to learn new things </li></ul><ul><li>Experimentation can be costly </li></ul><ul><li> Change and unpredictability may favor flexible problem solving </li></ul>
  9. 9. Flexible Problem Solving <ul><li>Cognitive abilities evolve to solve the adaptive problems a species faces </li></ul><ul><li>What are the adaptive problems that seem to have been most important in the evolution of primate intelligence? </li></ul><ul><li>Many theories have been proposed. We will discuss two main ones: </li></ul><ul><ul><li>Cognitive skills evolved primarily to solve ecological problems (the ecological intelligence hypothesis ) </li></ul></ul><ul><ul><li>Cognitive skills evolved primarily to solve social problems (the social intelligence hypothesis ) </li></ul></ul>
  10. 10. Learning and problem solving may also be useful in other contexts too <ul><li>Solving complex ecological problems </li></ul><ul><ul><li>Processing inaccessible food items </li></ul></ul><ul><ul><li>Locating and remembering food sources </li></ul></ul><ul><ul><li>Navigating between food sources </li></ul></ul><ul><li>Solving complex social problems </li></ul><ul><ul><li>Keeping track of kin </li></ul></ul><ul><ul><li>Keeping track of relative rank </li></ul></ul><ul><ul><li>Remembering benefits given & received </li></ul></ul><ul><ul><li>Manipulating rivals </li></ul></ul><ul><ul><li>Managing coalitions </li></ul></ul>
  11. 11. Testing Hypotheses <ul><li>Are ecological or social factors better predictors of brain (especially neocortex) size? </li></ul>
  12. 13. Ecological Intelligence Hypothesis <ul><li>Finding food is complicated </li></ul><ul><ul><li>Where is it? </li></ul></ul><ul><ul><li>What is edible? </li></ul></ul><ul><ul><li>When will food be available? </li></ul></ul><ul><ul><li>How to get from one food site to another </li></ul></ul><ul><ul><li>How to process food </li></ul></ul><ul><li>Two sub-hypotheses: </li></ul><ul><ul><li>Frugivory </li></ul></ul><ul><ul><li>Extractive Foraging </li></ul></ul>
  13. 14. Ecological Intelligence Hypothesis 1: Frugivory <ul><li>Exploiting short-lived, patchy food resources (fruits) may have favored special cognitive skills in primates </li></ul><ul><li>Frugivory demands: </li></ul><ul><ul><li>Knowledge of fruit properties </li></ul></ul><ul><ul><li>Complex spatial representations </li></ul></ul><ul><ul><li>Good memory </li></ul></ul>
  14. 15. What do primates know about fruit? <ul><li>Japanese macaques know </li></ul><ul><ul><li>Fruit grows on trees, candy doesn’t </li></ul></ul><ul><ul><li>When food is available </li></ul></ul><ul><ul><li>Properties of food </li></ul></ul><ul><li>Howler monkeys cope with toxins </li></ul><ul><ul><li>Many plants produce toxins as protection </li></ul></ul><ul><ul><li>Howlers are picky eaters </li></ul></ul><ul><ul><li>Howlers select leaves low in toxins </li></ul></ul>akebi fruit
  15. 16. What do primates know about maps? (Spatial representations) <ul><li>In tropical forests, huge diversity of plant species </li></ul><ul><li>In savanna habitats, very large ranges </li></ul><ul><li>“ Cognitive map”: mental representation of location, availability, and quality of things in environment </li></ul>
  16. 17. Primates would like google maps… <ul><li>Primates seem to know </li></ul><ul><ul><li>What is edible </li></ul></ul><ul><ul><li>Where food sites are located </li></ul></ul><ul><ul><li>When food will be available </li></ul></ul><ul><ul><li>How much food is available </li></ul></ul><ul><li>Example: Tamarins in Peru </li></ul><ul><ul><li>Feed on 100’s of different trees </li></ul></ul><ul><ul><li>Some species fruit synchronously </li></ul></ul><ul><ul><li>Tamarins visit many trees each day </li></ul></ul><ul><ul><li>70% of time move to nearest tree of same species that was not depleted </li></ul></ul><ul><ul><li>Don’t revisit trees </li></ul></ul>
  17. 18. Does frugivory correlate with large brains? A little, but not strongly
  18. 19. Looking at the correlation between the color vision portion of the brain and neocortex, the correlation is stronger <ul><li>Extent of frugivory may be related to brain size </li></ul><ul><ul><li>Frugivores tend to have bigger brains than folivores </li></ul></ul><ul><li>Barton 1998 </li></ul><ul><li>Parvocellular cells process wavelength & detailed color information </li></ul><ul><li>Large neocortex related to: </li></ul><ul><li>Diurnal activity </li></ul><ul><li>% frugivory in diet </li></ul><ul><li>Group size </li></ul>
  19. 20. Ecological Intelligence Hypothesis 2: Extractive Foraging <ul><li>Exploiting foods that are difficult to process, may have favored special cognitive skills in primates </li></ul><ul><li>Extractive foraging demands: </li></ul><ul><ul><li>Consumption of difficult-to-process foods </li></ul></ul><ul><ul><li>Complex, multi-step activities </li></ul></ul><ul><ul><li>Fine motor skills </li></ul></ul>
  20. 21. Examples of extractive foraging <ul><li>Baboons dig up underground food </li></ul>
  21. 22. Examples of extractive foraging <ul><li>Baboons dig up underground food </li></ul><ul><li>Capuchins extract food from </li></ul><ul><ul><li>Eggs </li></ul></ul><ul><ul><li>Rotten wood </li></ul></ul><ul><ul><li>Under bark </li></ul></ul><ul><ul><li>Hard shelled nuts </li></ul></ul><ul><ul><li>Spiny, sticky pods </li></ul></ul>
  22. 23. Examples of extractive foraging <ul><li>Baboons dig up underground food </li></ul><ul><li>Capuchins extract food from </li></ul><ul><ul><li>Eggs </li></ul></ul><ul><ul><li>Rotten wood </li></ul></ul><ul><ul><li>Under bark </li></ul></ul><ul><ul><li>Hard shelled nuts </li></ul></ul><ul><ul><li>Spiny, sticky pods </li></ul></ul><ul><li>Aye ayes extract insect larvae </li></ul><ul><ul><li>Insects burrow into wood, lay eggs </li></ul></ul><ul><ul><li>Tap tree trunk to locate larvae </li></ul></ul><ul><ul><li>Gnaw on branch to make pit </li></ul></ul><ul><ul><li>Use 3 rd finger to extract larvae </li></ul></ul>
  23. 24. <ul><li>Orangutans eat durian, neesia fruits </li></ul><ul><ul><li>Protected by tough or spiny shells </li></ul></ul><ul><ul><li>Pungent interior </li></ul></ul>Examples of extractive foraging
  24. 25. <ul><li>Mountain gorillas’ foods are abundant, but well defended </li></ul>Examples of extractive foraging bamboo wild celery thistles
  25. 26. <ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging Chimps fish for ants in tree nests
  26. 27. <ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging Chimps fish for termites
  27. 28. <ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging Chimps extract honey
  28. 29. <ul><li>Chimps eat many extractive foods </li></ul>Examples of extractive foraging West African chimps use rocks to bash open hard-shelled nuts
  29. 30. Does use of extractive foods correlate with large brains? Not really
  30. 31. Other problems with ecological intelligence hypothesis <ul><li>Extent of frugivory related to brain size </li></ul><ul><ul><li>Frugivores have bigger brains than folivores </li></ul></ul><ul><li>But, extractive foragers include: </li></ul><ul><ul><li>aye-ayes (relatively small brain) </li></ul></ul><ul><ul><li>apes (relatively large brain) </li></ul></ul><ul><li>And, small-brained animals: </li></ul><ul><ul><li>cognitive maps </li></ul></ul><ul><ul><li>navigate long distances </li></ul></ul><ul><ul><li>forage efficiently </li></ul></ul>
  31. 32. Social Intelligence Hypothesis <ul><li>Dunbar: “social intelligence” </li></ul><ul><li>Humphrey: “social chess” </li></ul><ul><li>Byrne & Whiten: “Machiavellian intelligence” </li></ul>
  32. 33. <ul><li>Primates live in relatively large groups </li></ul><ul><li>Primates track social information </li></ul><ul><ul><li>Identity </li></ul></ul><ul><ul><li>Group membership </li></ul></ul><ul><ul><li>Kinship </li></ul></ul><ul><ul><li>Dominance </li></ul></ul><ul><ul><li>Alliances </li></ul></ul><ul><li>Primates know about own relationships </li></ul><ul><li>Primate know about relationships of others </li></ul>Social challenges may favor large brains: Social Intelligence Hypothesis
  33. 34. <ul><li>Primates recognize others as individuals and keep track of group membership </li></ul><ul><li>Know members of own group </li></ul><ul><li>Respond aggressively to strangers </li></ul><ul><li>Know ranges of neighboring groups </li></ul><ul><li>Know individual members of neighboring groups </li></ul>Social Intelligence
  34. 35. <ul><li>Monkeys seem to know a lot about their own relationships </li></ul><ul><li>Distinguish kin from nonkin </li></ul><ul><li>Give submissive signals to dominant animals </li></ul><ul><li>Recruit support from those most likely to support them </li></ul>Social Intelligence
  35. 36. Social Intelligence <ul><li>Monkeys know about kinship relationships of others </li></ul><ul><li>When vervet infants scream, other females look toward mother </li></ul><ul><li>After fights, vervets reconcile with kin of former opponents </li></ul><ul><li>Vervets redirect aggression to kin of former opponents </li></ul>
  36. 37. Social Intelligence <ul><li>Triadic awareness of rank & friendship in some species </li></ul><ul><li>Is A better friends with B than A is with me? </li></ul><ul><li>Matters if I have a fight with B and ask A for help! </li></ul><ul><li>Capuchins & baboons have triadic awareness of this kind </li></ul>A B Self ?
  37. 38. Social Intelligence <ul><li>Baboons know something about others’ rank relationships </li></ul><ul><li>Grunt is affiliative call, scream is distress call </li></ul><ul><li>Baboons can recognize others’ calls </li></ul><ul><li>HRF make LRF scream, but </li></ul><ul><li>LRF never make HRF scream </li></ul><ul><li>Play normal sequence of calls: </li></ul><ul><li>HRF grunt, LRF scream </li></ul><ul><li>Play unlikely sequence of calls: </li></ul><ul><li>LRF grunt, HRF scream </li></ul><ul><li>Baboons react strongly to unlikely sequence </li></ul>
  38. 39. Social Intelligence <ul><li>Knowledge of others’ relationships useful when fights occur </li></ul><ul><li>Able to predict who will win contest </li></ul><ul><li>Able to predict who will support whom </li></ul><ul><li>Able to predict who will intervene against whom </li></ul><ul><li>Able to predict who will be effective ally </li></ul>
  39. 40. Social Intelligence <ul><li>Monkeys can predict what others will do </li></ul><ul><li>Macaques and baboons often grunt when they approach others </li></ul><ul><li>Grunts are reliable predictor of peaceful interaction </li></ul><ul><li>Grunting facilitates friendly contact </li></ul><ul><li>Grunting facilitates infant handling </li></ul>Does this mean monkeys can read other monkey’s minds?
  40. 41. A special kind of intelligence <ul><li>“ Theory of Mind” or “Mindreading” </li></ul><ul><li>The ability to infer what others think, want, or believe </li></ul><ul><li>And the ability to use this to understand and predict their behavior </li></ul><ul><li>Good evidence that humans have this </li></ul><ul><li>Other primates? </li></ul>
  41. 42. Theory of Mind <ul><li>In humans, ToM develops in early childhood </li></ul><ul><li>Common experiment to test for ToM </li></ul><ul><ul><li>Show child M&M tube </li></ul></ul><ul><ul><li>Ask what’s inside </li></ul></ul><ul><ul><li>Child will guess “M&Ms” </li></ul></ul><ul><ul><li>Show child tube contains pencil </li></ul></ul><ul><ul><li>Adult comes into room </li></ul></ul><ul><ul><li>Ask child what adult will think is in tube </li></ul></ul><ul><ul><li>Up to age 3, children say “pencil” </li></ul></ul><ul><ul><li>After 3-4, children say “M&Ms” </li></ul></ul><ul><li>Many other tests of this </li></ul><ul><li>Autism may be a deficit specifically in theory of mind </li></ul>
  42. 43. <ul><li>Monkeys appear to know relatively little about what others know </li></ul><ul><li>Vervet mothers don’t warn infant about dangerous things that they see, but infant doesn’t see </li></ul><ul><li>Don’t do well on tasks that require taking another perspective </li></ul><ul><li>Don’t practice deception (often) </li></ul><ul><li>But: we might not have devised a good way of testing ToM in monkeys; this happened with apes </li></ul>Theory of Mind
  43. 44. Theory of Mind <ul><li>Apes may know more about what others know </li></ul><ul><li>Recognize self in mirror </li></ul><ul><li>Can discern others’ intent </li></ul><ul><li>Alert others to dangers they haven’t seen </li></ul><ul><li>Can deceive others </li></ul><ul><li>Political maneuvering </li></ul>
  44. 45. Do Chimps have theory of mind? (Povinelli et al. 1996) Test whether seeing = knowing <ul><li>Chimps allowed to chose which of two humans to beg from </li></ul><ul><li>Consistently prefer to beg from a forward-facing human </li></ul>
  45. 46. But they do not prefer… <ul><li>Human w/eyes open to human w/eyes closed </li></ul><ul><li>Human w/blindfold over mouth to human w/blindfold over eyes </li></ul><ul><li>Human w/bucket on shoulder to human w/bucket over head </li></ul><ul><li>Human w/back turned while looking over her shoulder at the chimp to human w/back turned while looking away from chimp </li></ul>
  46. 47. But: chimps are sensitive to what others know in food competition <ul><li>Brian Hare and colleagues devised a test of theory of mind using food competition </li></ul><ul><li>In chimps, dominant will always get food from subordinates </li></ul><ul><li>Hare et al. placed food so subordinate could see it, but dominant could not – and subordinate knew dominant could not </li></ul><ul><li>Subordinate would take food only when they knew dominant could not see it </li></ul>Dominant Subordinate Food
  47. 48. Ecological Realism <ul><li>Often, lab tests like Povinelli’s are poor tests </li></ul><ul><li>Don’t look at skills being used in ecologically realistic contexts in which they evolved </li></ul>
  48. 49. Other contexts of mindreading we haven’t studied much… <ul><li>Cooperative hunting </li></ul><ul><li>Stalking prey </li></ul><ul><li>Avoiding predators </li></ul>
  49. 50. Apes’ cognitive abilities are hotly debated <ul><li>Some think apes have considerable knowledge of others’ minds </li></ul><ul><ul><li>Mind-reading </li></ul></ul><ul><ul><li>Deceit </li></ul></ul><ul><ul><li>Compassion & empathy </li></ul></ul><ul><ul><li>Imitation </li></ul></ul><ul><ul><li>Moral sentiments </li></ul></ul><ul><li>Others think apes have very little knowledge of others’ minds </li></ul><ul><ul><li>Sophisticated social learning capacities </li></ul></ul><ul><ul><li>But little true understanding of others’ minds </li></ul></ul>
  50. 51. Testing Hypotheses <ul><li>Are ecological or social factors better predictors of brain (especially neocortex) size? </li></ul>
  51. 52. Figure 09.07c Does social complexity correlate with large brains? Yes: better than with frugivory or extraction
  52. 53. Except… <ul><li>Social intelligence hypothesis doesn’t explain why apes are smarter than monkeys </li></ul><ul><li>Apes all live in relatively small groups </li></ul><ul><ul><li>Chimp and bonobo groups rarely > 50 </li></ul></ul><ul><ul><li>Gorilla groups < 20 </li></ul></ul><ul><ul><li>Orangs solitary </li></ul></ul><ul><li>What favored evolution of enhanced cognitive abilities in apes? </li></ul><ul><ul><li>Apes do use lot of extractive foods </li></ul></ul><ul><ul><li>Some foraging skills take long time to learn </li></ul></ul><ul><ul><li>Big brain may be linked to foraging challenges </li></ul></ul><ul><li> Complete explanation may require multiple selective pressures </li></ul>
  53. 54. Big brains may also be linked to particular types of social challenges <ul><li>Generally larger neocortex ratio as clique size (within a social group) increases </li></ul><ul><li>Simians use more “computing power” for the same clique size as prosimians </li></ul><ul><li>Terrestrial simians more similar to apes than arboreal simians </li></ul><ul><li>Hominoids use more “computing power” for the same clique size as simians </li></ul>Kudo & Dunbar 2001
  54. 55. Brain size may be the result of selection for flexible behavior in BOTH ecological & social domains <ul><li>Compare “executive brain” ratio </li></ul><ul><ul><li>Innovation - novel solutions to social & environmental problems </li></ul></ul><ul><ul><li>Social learning - learn skills and information from others </li></ul></ul><ul><ul><li>Tool use </li></ul></ul>Laland & Reader 2002
  55. 56. So which is it? Ecological or social intelligence that drove primate brain growth? <ul><li>Answer isn’t clear </li></ul><ul><li>Unlikely to be one or the other </li></ul><ul><li>Both likely operating at the same time or in alternation over evolutionary history </li></ul><ul><li>How does the intelligence of species in other taxa inform this question? </li></ul>http://www.youtube.com/watch?v=R6KvPN_Wt8I

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